The present invention relates to an RF "patch" antenna employing a strip line feed element.
In many applications, small patch antennas are used to radiate microwave energy in a defined location. For example, such antennas are employed in passive and active radar systems to detect the presence, location and identity of objects within the radar beam. For example, such objects may carry active or passive transponders which are interrogated by the radar beam.
One such system which utilizes passive transponders is disclosed in the commonly-owned patent application Ser. No. 509,523, filed June 30, 1983, entitled "System for Interrogating a Passive Transponder Carrying Phase-Encoded Information".
A system of this kind is often installed on the wall of a building or housing structure at a point--near a door, gate, conveyor or railroad tracks--where the objects to be interrogated pass by. It is desirable that the antenna be easily adjustable upon installation, and also after installation, so that the radiated beam may be properly directed toward the object to be interrogated. It is also desirable to eliminate the requirement for direct electrical connection to antenna parts that need to be selected, during the system installation, or subsequently changed in the field.